---
arch/powerpc/kernel/pci-common.c | 66 ++++++++++++++++++++++++++++++++++++++--
1 file changed, 63 insertions(+), 3 deletions(-)
v5:
* Improved comments.
* Changed the the Fixed PHB Numbering to set the PHB number bit
on the bitmap anyway, avoiding issues when system has virtual PHBs.
* Changed the device-tree check order - now, firstly we check for
"ibm,opal-phbid" and if it's not available, we try the pSeries case.
v4:
* Minor change (if/else nesting rearranged).
v3:
* Made the bitmap static.
* Rearranged if/else statements of Fixed PHB checking.
* Improved bitmap checkings, by removing loop and using instead the
find_first_zero_bit() function.
* Removed the single-statement function release_phb_number() by
adding its logic directly into pcibios_free_controller().
*Added check for bitmap size before clearing bit, avoiding memory
corruption.
v2:
* Added the Fixed PHB Numbering mechanism based on device-tree
properties.
* Changed list approach to bitmap on the Dynamic PHB Numbering
mechanism.
diff --git a/arch/powerpc/kernel/pci-common.c b/arch/powerpc/kernel/pci-common.c
index 0f7a60f..ad423c1 100644
--- a/arch/powerpc/kernel/pci-common.c
+++ b/arch/powerpc/kernel/pci-common.c
@@ -41,11 +41,17 @@
#include <asm/ppc-pci.h>
#include <asm/eeh.h>
+/* hose_spinlock protects accesses to the the phb_bitmap. */
static DEFINE_SPINLOCK(hose_spinlock);
LIST_HEAD(hose_list);
-/* XXX kill that some day ... */
-static int global_phb_number; /* Global phb counter */
+/* For dynamic PHB numbering on get_phb_number(): max number of PHBs. */
+#define MAX_PHBS 8192
+
+/* For dynamic PHB numbering: used/free PHBs tracking bitmap.
+ * Accesses to this bitmap should be protected by hose_spinlock.
+ */
+static DECLARE_BITMAP(phb_bitmap, MAX_PHBS);
/* ISA Memory physical address */
resource_size_t isa_mem_base;
@@ -64,6 +70,55 @@ struct dma_map_ops *get_pci_dma_ops(void)
}
EXPORT_SYMBOL(get_pci_dma_ops);
+/* get_phb_number() function should run under locking
+ * protection, specifically hose_spinlock.
+ */
+static int get_phb_number(struct device_node *dn)
+{
+ const __be64 *prop64;
+ const __be32 *regs;
+ int phb_id = 0;
+
+ /* Try fixed PHB numbering first, by checking archs and reading
+ * the respective device-tree properties. Firstly, try PowerNV by
+ * reading "ibm,opal-phbid", only present in OPAL environment.
+ */
+ prop64 = of_get_property(dn, "ibm,opal-phbid", NULL);
+ if (prop64) {
+ phb_id = (int)(be64_to_cpup(prop64) & 0xFFFF);
+
+ } else if (machine_is(pseries)) {
+ regs = of_get_property(dn, "reg", NULL);
+ if (regs)
+ phb_id = (int)(be32_to_cpu(regs[1]) & 0xFFFF);
+ } else {
+ goto dynamic_phb_numbering;
+ }
+
+ /* If we have a huge PHB number obtained from device-tree, no need
+ * to worry with the bitmap. Otherwise, we need to be sure we're
+ * not trying to use the same PHB number twice.
+ */
+ if (phb_id < MAX_PHBS) {
+ if (test_bit(phb_id, phb_bitmap))
+ goto dynamic_phb_numbering;
+ set_bit(phb_id, phb_bitmap);
+ }
+
+ return phb_id;
+
+ /* If not pSeries nor PowerNV, or if fixed PHB numbering tried to add
+ * the same PHB number twice, then fallback to dynamic PHB numbering.
+ */
+dynamic_phb_numbering:
+
+ phb_id = find_first_zero_bit(phb_bitmap, MAX_PHBS);
+ BUG_ON(phb_id >= MAX_PHBS); /* Reached maximum number of PHBs. */
+ set_bit(phb_id, phb_bitmap);
+
+ return phb_id;
+}
+
struct pci_controller *pcibios_alloc_controller(struct device_node *dev)
{
struct pci_controller *phb;
@@ -72,7 +127,7 @@ struct pci_controller *pcibios_alloc_controller(struct device_node *dev)
if (phb == NULL)
return NULL;
spin_lock(&hose_spinlock);
- phb->global_number = global_phb_number++;
+ phb->global_number = get_phb_number(dev);
list_add_tail(&phb->list_node, &hose_list);
spin_unlock(&hose_spinlock);
phb->dn = dev;
@@ -94,6 +149,11 @@ EXPORT_SYMBOL_GPL(pcibios_alloc_controller);
void pcibios_free_controller(struct pci_controller *phb)
{
spin_lock(&hose_spinlock);
+
+ /* Clear bit of phb_bitmap to allow reuse of this PHB number. */
+ if (phb->global_number < MAX_PHBS)
+ clear_bit(phb->global_number, phb_bitmap);
+
list_del(&phb->list_node);
spin_unlock(&hose_spinlock);
--
2.1.0
--
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